This application is based on application Nos. H11-149893, H11-236724, and H11-372605 filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a semiconductor memory card that stores audio data, still image data and control data, and to a playback apparatus, recording apparatus, playback method, recording method, and computer-readable recording medium relating to such a semiconductor memory card. In particular, the present invention relates to improved storage of audio data and control data distributed as contents by a content distribution service, such as an electronic music distribution service.
2. Description of Background Art
Electronic music distribution enables users to purchase and receive music contents (e.g., songs and albums) via the Internet. Such technology has the potential to greatly increase the market for recorded music and is gradually becoming possible as the necessary hardware infrastructure is implemented. One way to store music contents that are obtained from an electronic music distribution service is on semiconductor memory cards whose portability makes them ideal. Accordingly, a great increase is expected in the demand for such cards.
Various kinds of semiconductor memory cards are available, such as Flash ATA cards and Compact Flash cards. Music contents can also be stored onto disc media, such as CD-R (Compact Disc-Recordable) or MiniDisc (MD). While there are a great variety of recording media that can be used for recording music contents, there are only a limited number of methods for indicating where the playback of a music content (track) should start. This operation is generally performed according to one of the following patterns.
When a music album is composed of a plurality of music contents (tracks), there are two main methods for indicating where the playback should start. The first method has the playback start from the first track in the album. The second method has the user indicate a track number and then has the playback start from the beginning of the indicated track.
In the first of these methods, the playback always starts with the same track and continues through all of the tracks in the album in the same order. If the user stops the playback midway through the album, recommencing the playback according to this method will result in the playback apparatus returning to the first track. The user will therefore end up having to listen to tracks that have just been played.
In the second method, the playback starts from the track indicated by the user. When the user stops the playback at a given point in the album and then starts playback once again, the user can have the playback restart from any track, such as the track following the track where playback was stopped. This means that the user does not have to listen to the tracks from the start once more. In this latter case, however, the user will still have to make several operations, such as inputting a track number. This can be troublesome, especially if the user does not know which track corresponds to which track number. In such cases, the user may indicate the wrong track, which will then be played back by the playback apparatus.
As described above, when playback is stopped and then recommenced, the two methods currently used either force the user to listen to all of the tracks in order from the beginning or to input a track number for the track from which the playback should start. This is far from ideal.
The following two methods are also sometimes used to indicate a position at which playback should commence. A third method has the user indicate a move of the playback position to a desired start time within a desired track using a forward or backward search function provided by a playback apparatus. A fourth method has the user indicate a desired track and a desired position within this track using a jog dial (or the like) and then commences reproduction from this position. Since both methods have the user indicate how far the playback previously progressed, they have the same drawback as the second method described above.
Current MiniDisc (MD) playback apparatuses use a reproduction method that indicates the playback position in a more user-friendly manner than the first to fourth methods given above.
When the user stops the playback of an MD, resume information showing the position where playback stopped is recorded in a nonvolatile memory in the MD player. When the user indicates playback of the same MD, the playback of the tracks recorded on the MD starts at the position given in the resume information.
The resume information is recorded in the MD player in a nonvolatile manner so that an interruption to the power supply does not result in the loss of the information. This means that the user can listen to part of a music album, turn off the player, and still have the playback resume at the position where playback was stopped. In this case, the user does not have to repeatedly listen to the tracks at the start of the album as in the first method, or to have to input a track number as in the second method, making this an ideal way to listen to all of the tracks included in an album.
With an MD, however, the resume information showing how far an album has been played back is stored within the hardware of the MD player. Accordingly, there is the problem that when an MD is ejected from a player and inserted into another player, the second player will play back the tracks on the MD starting from the first track in the album, in the same way as the first method.
As a specific example, when a user listens to some of the tracks on an album using a first playback apparatus, stops the playback, and then transfers the disc to another playback apparatus, this second playback apparatus will not store resume information showing the position reached by the playback of this disc. As a result, the playback will start from the start of the album and so make the user listen to the same tracks again.
Since discs are rarely transferred from one player to another during the playback of an album, the playback returning to the start of the album may not be such a significant problem. When the album is subjected to electronic music distribution before being recorded onto a recording medium, however, it is believed that there will be many cases where an album will be partially played back on one player and then transferred to another.
Electronic music distribution is achieved by having a computer owned by the user download a music album from a server computer operated by a record label. The user can then have the downloaded album played back on their computer. Since modern personal computers are capable of playing back music contents, users can listen to albums they have bought on their computer. Assume that the user listens to the album on a portable playback apparatus after listening to it on his/her computer.
In this case, the portable playback apparatus cannot know how far playback by the computer progressed, so that the album will be played back once again from the start. As the user will be subjected to the same songs that were played back by the computer, the user is likely to tire of the album quicker than if all of the tracks were played back.
As recording media become smaller and lighter, though larger in capacity, it becomes increasingly possible to record albums containing large numbers of tracks onto a single recording medium. It is believed that such a recording medium will often be transferred between playback apparatuses. If the playback returns to the beginning after a large number of tracks have been played, this will be very annoying for listeners.
It is a first object of the present invention to provide a semiconductor memory card that enables playback to be resumed from a previously stopped position without the same recorded material being played back and without a user having to indicate the playback position, even when the semiconductor memory card has been transferred between playback apparatuses.
It is a second object of the present invention to provide a semiconductor memory card that enables a playback apparatus to recommence the playback of an album that was commenced on a different playback apparatus without the same recorded material being played back.
The first object can be achieved by a semiconductor memory card, storing: an audio sequence in which a plurality of audio objects are arranged; and resume information showing a resume position for use when playback of the audio sequence resumes midway through the audio sequence.
Assume that an audio sequence corresponds to a music album, and that the user listens to a first part of the album on a playback apparatus. If the user then transfers the semiconductor memory card to another playback apparatus, this playback apparatus will be able to recommence the playback of the album at the stopped position by referring to the playback resume position shown by the resume information.
The resumption of playback based on the resume information does not require the user to make any particular operation. This means that the user does not have to go to the trouble of indicating a track (audio object) when transferring the semiconductor memory card to another playback apparatus.
The resume information may include at least one of type 1 position information and type 2 position information, the type 1 position information showing a type 1 resume position set according to a user operation, and the type position information showing a type 2 resume position that was automatically set when playback of the audio sequence last stopped.
Here, each audio object in the audio sequence may be provided with unique identification information, the type 1 position information showing the type 1 resume position using the identification information of one of the audio objects, and the type 2 position information showing the type 2 resume position using the identification information of one of the audio objects and time information showing an offset from a start of the one of the audio objects to the type 2 resume position.
The second object is achieved by the above construction. The type 2 position information includes an offset from the start of an audio object. When the semiconductor memory card is transferred between playback apparatuses, the second playback apparatus can commence playback at a position immediately following a point where playback by the first playback apparatus was stopped. This means that a user can start to listen to an album on a first playback apparatus, stop the playback, transfer the semiconductor memory card to another playback apparatus, and then have the playback continue from right after the stopped position. Unlike conventional technologies, the user does not have to put up with hearing the same tracks whenever the semiconductor memory card is transferred between playback apparatuses.
Albums obtained from an electronic music distribution service will often be transferred between different playback apparatuses. In such case, however, the user will not have to listen to the same tracks whenever the album is transferred to another playback apparatus.